Welt insole



April 25, 1944. w, Q WRIGHT 2,347,530

WELT INSOLE Filed April 8 1942 Patented Apr. 25, 1944 warren stares Parana caries 3 Claims.

My present invention is a welt insole for use in the manufacture of boots and shoes, particularly directed to the making of flexible footwear.

In my development of insole structures, utilizing an initially and permanently yielding sewing rib of plastic material, such as plasticized polyvinyl resins of such plastic material of the general type illustrated in my prior and copending application Ser. No. 413,500, or of permanently yielding and resilient fibrous material such as shown in my prior and copending application Ser. No. 421,974, same may be combined with extremely thin flexible leather, such as ordinary upper leather, consequently resulting in a welt insole using upper leather as the insole material and a sewing rib secured to the marginal surface of the same.

Heretofore it has been considered impractical to utilize as thin, flexible, and pliable a material as ordinary upper leather for use as an insole, but I find that the combination of upper leather, together with a sewing rib and flange of the type shown in my said copending application, produce a new and ideal insole structure particularly for use in the manufacture of flexible footwear. The permanent yielding and flexible structure of the plastic sewing rib and flange material, when combined with upper leather, gives sufficient rigidity to the upper leather to enable the same to be used advantageously as a welt insole, while the yielding pliability and flexibility of such upper leather and similar qualities of the yielding rib structure present a permanently flexible and yielding insole structure which improves the shoe madetherewith and renders the resultant shoe structure initially and permanently flexible to a degree heretofore considered impossible where a leather insole was employed. -My discovery. that the combination of a thin upper leather insole blank with a yielding plastic rib and flange, which rib and flange is of a plastic polyvinyl resin material, such as Koroseal, Vinylite, or the like, produces a resultant welt insole with a sewing rib and insole blank of substantially identical coemciency of softness, pliability, and permanent flexibility as well, as of uniform quality, which I believe is a distinct novelty in this art.

The flange, particularly, is important not only prevents the rib from guttering the inside of the insole after the shoe is made. The fairly broad bearing of the flange seems to be beneflciai in this respect.

Furthermore, my process, which consists in starting with a hide of thin flexible upper leather, cutting out insole blanks from such upper leather by clicking machine methods or otherwise, as distinguished from the prior art method of cutting rough insole blanks with squared ends and rough-rounded contours, which afterward had to be trimmed, is also an important step in the process. By my method, I eliminate the present prior art procedure of first cutting roughblanks, then putting them thru atrimming machine operation to round off corners, edges, and reduce the area of the rough blank, which produces a great deal of waste.

My present method cuts the insole blank from upper leather in its final finished contour, area, and size and with the blank so formed, they can be immediately fitted with the sewing rib by securing the attaching flange of the rib of plasticized polyvinyl resin, or other non-rubber plastic material, by a suitable adhesive, presenting a simple, speedy, and economical method of manufacturing an insole.

Also, an important feature consists in the fact that the upper leather presents a highly desirable and flnished foot-contacting surface on the inside of the shoe, thus eliminating the necessity of adding a sock lining or the like. The flange being preferably cemented to the opposite surface of the insole gives a. reinforcing and strengthening of the entire shoe structure at the marginal edge.

Referring to the drawing illustrating the present invention and a preferred method of carrying out the same;

Fig. 1 is a diagrammatic view of an upper leather skin after the same is tanned and ready for cutting, showing the method of cutting therefrom a-plurality of divergently positioned insole blanks;

Fig, 2 is a plan view on an enlarged scale illustrating the application of a sewing rib, of nonrubber plastic material, to the blank;

Fig. 3 is a cross-sectional view showing the rib and attached flange to the insole upper leather blank by adhesive;

Fig. 4 is a cross-sectional view on the line 4-4 of Fig. 2.

As shown in the drawing, a hide or skin I of contour, and of any dimension desired. Blanks of differing dimensions can, of course, be cut from the same hide I, and the simple, economical, and well-known method of cutting out upper leather by clicking machines can be utilized for this purpose.

The resultant insole blank 2 is completely and accurately formed at this single operation and eliminates entirely the prior method of cutting sole leather into strips and then cutting rough blanks, by a beam dinker or a Knox blocker, with a single line of contour between adjacent blanks widthwise of the strip which-produces only rough blocks or blanks with squared ends, and of greater dimensions than that of .the resultant blank to be made therefrom, necessitating the further operation of trimming into final contour, and producing considerable waste leather.

The insole blank as thus cut is then coated with adhesive 3 around the marginal edge of the fleshy side 4, leaving the finished grain side 5 of the upper leather for the inside of the shoe, and thus giving a finished foot-contacting surface independently of a sock lining, as above explained.

My novel rib, of a plasticized polyvinyl resinous material, as explained in my said prior application, and having an upstanding edge ID of sumcient height and form to constitute a sewing rib,

' flange i2 formed for attachment to the insole 2,

is applied to the marginal portion of the rib and secured by the adhesive 3. The inner portion of the attaching flange is preferably serrated or cut, as shown, presenting a series of separate portions M, which facilitates the application of the flange and rib to the uneven contours of the insole blank, particularly at the toe and shank portions.

WhileI have illustrated the adhesive 3 as applied to the surface of the insole blank, this can, of course, be applied tothe contacting face of the attaching flange or'to both the flange and the insole.

Also, the flange i2 may be, and preferably is, of sufficient area to extend as close to the marginal edge of the upper leather blank 2 as'may be'necessary to stiffen the edge portion and ream, tate the holding of the insole blank margin closely to the last during the lasting operation, as well as during the inseam stitching operation. This feature of stiffening the edge while still'rn'ain- ,taining pliability and flexibility both in the inupstanding rib member and a horizontal attaching flange, is useful with the rib and flange member of various materials, as above noted, I prefer to employ a flange and rib structure which will give suitable reinforcement to the thin leather material and thus strengthen the marginal edge portion while still maintaining flexibility substantially coextensive with the pliability of the upper leather, and I prefer at present to utilize a synthetic plastic for this rib and flange structure because it can be readily manufactured in long lengths in an economical way.

I have discovered that a suitable plastic material can be made out of the well-known standard articles such as Koroseal, Vinylite, or the like. Such plastics have an initial and permanent strength and elasticity as well as a stitch-retaining capacity and permanent pliability which lends itself peculiarly beneficial in reinforcing the thin upper leatherinsole layer, while simulating the permanent pliability of the upper leather itself.

Such materials as Koroseal, Vinylite, or the like are, therefore, intended to be used for the plastic rib structure which may be compounded with a hardness of approximately -82 as measured by a Shore durometer, and a tensile strength at rupture of 2500 pounds to 3500 pounds per square inch.

These limitations are, of course, for illustrative purposes only but are typical of plasticized poly-.

vinyl resinous materials, which may be employed as the rib and attaching flange structure of a nonrubber plastic.

I claim:

1. A welt insole comprising an insole blank of flexible upper leather, with its finished grain surface constituting a foot-contacting portion, in combination with a sewing rib of Koroseal secured to the marginal portion of the unfinished surface of the blank, said rib having a hardness of approximately 80 to 82 as measured on a Shore flexible upper leather, with its finished grain surface constituting a foot-contacting portion, in

'combination with a sewing rib of Koroseal adhesively secured to'the marginal portion of the fleshy side of the blank, said rib having an 'upstanding portion and a horizontal attaching flange, both rib and flange being of a hardness of approximately 80 to 82 as measured on a Shore durometer, and with a tensile strength of 2500 to 3500 pounds per square inch at rupture.

3. A welt insole of the kind described, comprising an insole blank of flexible upper leather, with its finished grain surface constituting a foot-contacting portion of the insole, in combination with a sewing rib of synthetic plastic material adhesively secured to the marginal portion of the unfinished surface of the blank, said material having the toughness, flexibility, and characteristics of Koroseal, Vinylite, or the like.

WALLACE C. WRIGHT. 

